1. Field of the Invention
The invention relates to the field of vacuum "pumping" systems for extracting fluids from difficult access areas such as engine crankcases, and transmission reservoirs. Specifically, the invention relates to a vacuum operated pumping system which extracts viscous fluids through small diameter openings (e.g., engine crankcases through oil dipstick holes).
2. Related Art
Many oil pumping systems for marine, automotive, aviation and stationary engines have been proposed. These systems have evolved to facilitate the periodic oil change requirement for these engines.
The primary factor driving the evolution of these extraction systems is the limited access underneath or difficult access to an engine's gravity drain system. Most attempts to alleviate these access problems have been directed toward manual or electric pumping systems, which pump oil or other fluid up through a small tube inserted through the engine dipstick tube. By design, these systems use "pumping" techniques which are constrained by physics to apply only a small psi force to the oil or other fluid without the application of excessive electrical horsepower. Due to the compressibility characteristics of air in conjunction with viscous fluids, pumping techniques using suction, which rely on a partial vacuum, cannot achieve the pulling force of a near absolute vacuum. In addition, the pumps of such systems often require external sources of power, such as electric power, which may not be readily available. Thus, many systems presently in use are operationally difficult. Moreover, their designs are inherently prone to oil spills, since most systems do not provide an acceptable container for transporting waste oil or other fluid to a proper disposal facility.
Conventional pumping systems which employ partial vacuums also cannot utilize the full capacity of the tank or canister. This is because the incoming incompressilbe fluid rapidly begins compressing the remaining air in the partial vacuum canister, thereby reaching pressure equalization before the canister capacity is consumed. Pumping rates of systems which employ vacuum techniques also fail to provide a constant rate of pumping because only a partial vacuum is available initially. As the tank accepting the waste fluid becomes filled, the rate of pumping slows down due to the partial vacuum.
For the reasons stated above, there exists a need for a thorough, clean, pumping system that works efficiently and provides an appropriate receptacle for waste fluid until disposition.